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Surface diffusivity of atomic deuterium on Ni_3(Al, Ti)(110) surface with and without boron

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中国有色金属学会会刊：英文版 2002年第4期12卷 649-652页

作者： j.L.Wang y.W.chung DepartmentofMaterialsScienceandEngineering RobertR.McCormickSchoolofEngineeringandAppliedScienceNorthwesternUniversityEvanstonIL60208USA DepartmentofMaterialsScienceandEngineering RobertR.McCormic

The electron stimulated desorption was used to measure the surface diffusivity of atomic deuterium on clean and boron modified Ni 3(Al, Ti)(110) surfaces. Boron dosing was performed using a solid state boron ion source. Earlier studies showed that boron dissociates water readily at temperatures as low as 130?K and that the resulting atomic hydrogen is bound to the surface strongly. The surface diffusion coefficient of atomic D on 0.05 monolayer boron modified surface was measured to be about 10 times smaller than that on the clean surface. This slower diffusion of atomic hydrogen may explain why boron improves the ductility of polycrystalline Ni 3Al in moist environments.

关键词：氘原子表面扩散硼 Ni3Al Ni3Ti 金属间化合物

Heavy Metals in Brown Rice(Oryza sativa L.) and Soil After Long-Term Irrigation of Wastewater Discharged from Domestic Sewage Treatment Plants

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Pedosphere 2011年第5期21卷 621-627页

作者： B.y.chung C.H.SONG B.j.PARK j.y.CHO Advanced Radiation Technology Institute Korea Atomic Energy Research Institute(KAERI) Korea Testing & Research Institute(KTR) Department of Horticultural Science Chungbuk National University Department of Bio-environmental Chemistry Chonbuk National University

A pot experiment was conducted in a plastic film house to evaluate the translocation and uptake of heavy metals(Pb,Cd,Cu,and Zn) into brown rice(Oryza sativa L.) and the heavy metals residues in soils which had previously been irrigated with domestic wastewater for a long time(3 years).The range of Pb,Cd,Cu,and Zn was 5.10 ± 0.01,0.105 ± 0.017,5.76 ± 0.42,and 23.56 ± 1.40 mg kg-1,respectively in the domestic wastewater-irrigated soil,and 0.370 ± 0.006,0.011 ± 0.001,0.340 ± 0.04,and 2.05 ± 0.18 mg kg-1,respectively,in the domestic wastewater-irrigated brown *** results indicated that application of domestic wastewater to arable land slightly increased the levels of Pb,Cd,Cu,and Zn in soil and brown rice(P y metals in brown rice were lower than the recommended tolerable levels proposed by the joint FAO/WHO Expert Committee on Food ***,the continuous monitoring and pollution control of hazardous materials from domestic wastewater are needed in order to prevent excessive build-up of heavy metals in the food chain.

关键词： accumulation domestic wastewater ground water irrigation P2O5 total N

Design Features and Commissioning of the Versatile Experiment Spherical Torus (VEST) at Seoul National University

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Plasma Science and Technology 2013年第3期15卷 244-251页

作者： K.j.chung y.H.AN B.K.jUNG H.y.LEE C.SUNG y.S.NA T.S.HAHM y.S.HWANG Department of Nuclear Engineering Seoul National University

A new spherical torus called VEST （Versatile Experiment Spherical Torus） is designed, constructed and successfully commissioned at Seoul National University. A unique design feature of the VEST is two partial solenoid coils installed at both vertical ends of a center stack, which can provide sufficient magnetic fluxes to initiate tokamak plasmas while keeping a low aspect ratio configuration in the central region. According to initial double null merging start-up scenario using the partial solenoid coils, apprdpriate p6wer supplies for driving a toroidal field coil, outer poloidal field coils, and the partial solenoid Coils are fabricated and successfully commissioned. For reliable start-up, a pre-ionization system with two cost-effective homemade magnetron power supplies is also prepared. In addition, magnetic and spectroscopic diagnostics with appropriate data acquisition and control systems are well prepared for initial operation of the device. The VEST is ready for tokamak plasma operation by completing and commissioning most of the designed components.

关键词： spherical torus partial solenoids double null merging start-up

Development of a group support system to support collaborative works in value management workshops

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journal of Harbin Institute of Technology(New Series) 2004年第1期11卷 91-97页

作者： chung j K H Dept. of Building and Real Estate Hong Kong Polytechnic University Kowloon Hong Kong China

Value Management (VM) is a rigorous and systematic approach to improve the value and optimise the overall cost of a facility. It identifies opportunities to remove unnecessary costs while assuring that quality, reliability, performance, and other critical factors will meet or exceed the customers’ expectations. It has been widely used in the construction industry in a number of countries. A recent survey, however, revealed several problems that hinder the wider use of this methodology in the industry. To overcome these problems, a feasibility study has been conducted to investigate whether or not a Group Support System (GSS) can support collaborative works in VM workshops. This paper introduces the development and structure of a prototype GSS which is designed to support the collaborative works of stakeholders in VM workshops. It begins with an introduction to the conceptual GSS framework and job plan, illustrating what GSS supports can be provided to VM workshops. This is followed by a detailed description of the GSS prototype system to demonstrate how these supports can be performed as an integrated computer system. The testing of the system is also discussed. The research findings provide strong evidence in supporting the notion of using GSS to improve VM implementation. The information support of GSS has been ranked to be the most useful GSS functions and most of the practitioners interviewed are highly interested in applying GSS to support VM workshops in the future.

关键词： group support system value management workshops construction

Hetero-deformation promoted strengthening and toughening in BCC rich eutectic and near eutectic high entropy alloys

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journal of Materials Science & Technology 2023年第15期146卷 1-9页

作者： D.H.chung j.Lee Q.F.He y.K.Kim K.R.Lim H.S.Kim y.yang y.S.Na Department of Special Alloys Extreme Materials Research InstituteKorea Institute of Materials ScienceChangwonThe Republic of Korea Department of Mechanical Engineering City University of Hong KongKowloon TongKowloonHong KongChina Graduate Institute of Ferrous Technology Pohang University of Science and TechnologyPohangThe Republic of Korea Center for Heterogenic Metal Additive Manufacturing Pohang University of Science and TechnologyPohangThe Republic of Korea Department of Materials Science and Engineering City University of Hong KongKowloon TongKowloonHong KongChina

Heterostructured eutectic high-entropy alloys(EHEAs)have attracted significant attention owing to their novel properties,such as balanced combinations of strength and fracture ***,the toughening/strengthening mechanisms of these EHEAs have not been thoroughly *** this study,we developed a series of dual-phase Al_((18–2x))Co_(30)Cr_((11+x))Fe_((11+x))Ni_(3)0(x=-1,0,1)eutectic and neareutectic HEAs containing face-centered cubic(FCC)and body-centered cubic(BCC)*** the high amount of BCC,which is referred to as the brittle phase,newly developed EHEAs exhibited superior fracture ***,we discovered that a fully eutectic HEA exhibited further improvements in both yield stress and fracture toughness,outperforming our off-eutectic and other previously reported *** combining experiments and theoretical models,we demonstrated that the synergistic increase in both strength and toughness in our fully eutectic HEA was derived from the high hetero-deformationinduced(HDI)strengthening/toughening associated with a high misorientation angle at the grain/phase boundaries.

关键词： Eutectic high entropy alloy Fracture toughness Heterogeneous structure Hetero deformation induced strengthening Misorientation angle

Challenges and opportunities for battery health estimation:Bridging laboratory research and real-world applications

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journal of Energy Chemistry 2024年第2期89卷 434-436,I0011页

作者： Te Han jinpeng Tian C.y.chung yi-Ming Wei Center for Energy and Environmental Policy Research Beijing Institute of TechnologyBeijing 100081China School of Management and Economics Beijing Institute of TechnologyBeijing 100081China Department of Electrical and Electronic Engineering and Research Centre for Grid Modernization The Hong Kong Polytechnic UniversityKowloon 999077Hong KongChina

Addressing climate change demands a significant shift away from fossil fuels,with sectors like electricity and transportation relying heavily on renewable *** to this transition are energy storage systems,notably lithium-ion *** time,these batteries degrade,affecting their efficiency and posing safety *** and predicting battery aging is essential,especially estimating its state of health(SOH).Various SOH estimation methods exist,from traditional model-based approaches to machine learning approaches.

关键词： Energy storage systems State of health Multi-source data Scientific AI Data-sharing mechanism

State-to-state Photoionization Dynamics of Vanadium Nitride by Two-color Laser Photoionization and Photoelectron Methods

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Chinese journal of Chemical Physics 2013年第6期26卷 669-678,I0003页

作者： Huang Huang Zhi-hong Luo yih chung Chang Kai-chung Lau C. y. Ng Department of Chemistry University of California Davis CA 95616 USA Department of Biology and Chemistry Oty University of Hone Kong Kowloon Hone Kong China

We have conducted a two-color visible-ultraviolet （VIS-UV） resonance-enhanced laser pho- toionization and pulsed field ionization-photoelectron （PFI-PE） study of gaseous vana- dium mononitride （VN） in the total energy range of 56900-59020 cm-1. The VN molecules were selectively excited to single rotational levels of the intermediate VN（D3H0, v＇=0） state by using a VIS dye laser prior to photoionization by employing a UV laser. This two-color scheme allows the measurements of rovibronically selected and re- solved PFI-PE spectra for the VN＋（X2A; v＋=0, 1, and 2） ion vibrational bands. By simulating the rotationally resolved PFI-PE spectra, j＋=3/2 is determined to be the lowest rotational level of the ground electronic state, indicating that the symmetry of the ground VN＋ electronic state is 2A3/2. The analysis of the PFI-PE spectra for VN＋ also yields accurate values for the adiabatic ionization energy for the formation of VN＋（X2A3/2）, IE（VN）=56909.5＋0.8 cm-1 （7.05588±0.00010 eV）, the vibrational fre- quency wc＋=1068.0±0.8 cm-1, the anharmonicity constant wc＋Xe＋=5.8±0.8 cm-1, the rotational constants Be＋=0.6563±0.0005 cm-1 and ae＋=0.0069±0.0004 cm-1, and the equi-librium bond length, re＋=1.529A, for VN＋（X2A3/2）; along with the rotational constants Bc＋=0.6578i0.0028 cm-1 and a＋=0.0085±0.0028 cm-1, and the equilibrium bond length re＋=1.527A for VN＋（X2As/2）, and the spin-orbit coupling constant A=153.3±0.8 cm-1 for VN＋（X2/k5/2,3/2）. The highly precise energetic and spectroscopic data obtained in the present study are valuable for benchmarking the predictions based on state-of-the-art ab initio quantum calculations.

关键词： Vanadium nitride Vanadium nitride cation Photoionization dynamics Two- color photoionization Pulsed field ionization-photoelectron Ionization energy Bond disso- ciation energy

Directly Modulated 10 Gb/s Signal Transmission over 320 km of Negative Dispersion Fiber for Regional Metro Network

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光学学报 2003年第S1期23卷 533-534页

作者： H. S. chung y. G. jang y. C. chung 1 Korea Advanced Institute of Science and Technology 373-1 Gusong-dong Yusong-gu Daejon 305-701 Korea2 Samsung Electronics 94-1 Imsudong Gumi KyungBuk 730-350 KoreaKorea Advanced Institute of Science and Technology 373-1 Gusong-dong Yusong-gu Daejon 305-701 Korea

We demonstrate the transmission of directly modulated 10-Gb/s WDM signals over 320 km of negative dispersion fiber (dispersion: -2.5 ps/km/nm @1550 nm) without dispersion compensation. The results indicate that a regional metro WDM network could be implemented cost-effectively by using the proposed negative dispersion fiber and direct modulated lasers.

关键词： of in et over Directly Modulated 10 Gb/s Signal Transmission over 320 km of Negative Dispersion Fiber for Regional Metro Network WDM for

Unusually high corrosion resistance in Mo_(x)CrNiCo medium entropy alloy enhanced by acidity in aqueous solution

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journal of Materials Science & Technology 2023年第8期139卷 59-68页

作者： S.Shuang G.j.Lyu D.chung X.Z.Wang X.Gao H.H.Mao W.P.Li Q.F.He B.S.Guo X.y.Zhong y.j.Wang y.yang Department of Mechanical Engineering College of EngineeringCity University of Hong KongKowloon TongKowloonHong KongChina State Key Laboratory of Nonlinear Mechanics Institute of MechanicsChinese Academy of SciencesBeijing 100190China School of Engineering Science University of Chinese Academy of SciencesBeijing 101408China State Key Laboratory of Solidification Processing Center of Advanced Lubrication and Seal MaterialsNorthwestern Polytechnical UniversityXi’an 710072China Unit of Structures Department of Materials Science and EngineeringKTHStockholm SE-10044Sweden Thermo-Calc Software Råsundav.18SolnaSE-16767Sweden Department of Materials Science and Engineering College of EngineeringCity University of Hong KongKowloon TongKowloonHong KongChina Institute of Advanced Wear&Corrosion Resistant and Functional Materials Jinan UniversityGuangzhou 510632China Department of Advanced Design and System Engineering College of EngineeringCity University of Hong KongKowloon TongKowloonHong KongChina

High corrosion resistance of alloys is essential for their structural applications;however,most alloys suffer from degradation of their corrosion resistance with the increasing acidity of their ***,we developed a series of medium-entropy alloys(MEAs)in this work,which ex-hibit high strength,superior fracture toughness and ultra-high corrosion resistance,outperforming the variety of corrosion resistant alloys hitherto *** interestingly,our MEAs exhibit an unusual anti-corrosion behavior and their corrosion resistance increases with acidity in Cl−containing *** extensive thermodynamic calculations,density functional theory(DFT)simulations and experi-ments,we reveal that the unusual anti-corrosion behavior of our MEAs can be attributed to their surface chemical complexity,which facilitates the physio-chemical-absorption of H_(2)O and O_(2)and thus the rapid formation of metastable medium entropy passive films that contain the lowest amount of defects,as compared to the passive films on conventional alloys reported in the literature.

关键词： Corrosion Passivation Alloy design Multi-principal element alloys Medium-entropy alloys